IBM Company Logical Reasoning Mathematical Reasoning

In 50 coins 1 is defective (more weight) .in how many weighs can u find the defective coin?

Read Solution (Total 2)

In 4 weighings, we can find defective coin.
12 years agoHelpfull: Yes(7) No(8)

6

Weigh 25 against 25......Weighing 1

The heavier side contains the dud. Discard the other 25.

Put one coin of the heavier set to one side.

Split the remaining 24 into 3 sets of 8. (A, B and C)

Weigh A against B......Weighing 2

If there is a heavier side, discard the other 16 plus the one coin you put to one side.

If there is not, weigh one set against the remaining 8......Weighing 3

If there is still no heavier group the one you put aside must be the dud coin.

If there is a heavier side take those 8 and weigh 4 against 4......Weighing 4

Take the heavier 4 and weigh 2 against 2......Weighing 5

Take the heavier pair and weigh one against one to find the dud......Weighing 6
9 years agoHelpfull: Yes(1) No(0)

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